Rex says
Same equations the textbooks use — just way less awkward. Pop in your stats and I'll tell you what the number actually means for you.
Try a scenario
Click to load — tweak from there.Inputs
Result
Cost per dose
$8.00
Cost per day
$16.00
Annual cost (cash price)
$5,840
Annual cost on generic
$535
Annual cost at your copay
$852
Psst — share this and help Rex grow
One click, a permanent link with your numbers baked in.
How to use this
- 1Enter price per package ($).
- 2Enter doses per package.
- 3Enter doses per day.
- 4Enter generic package price ($).
- 5Enter your copay per fill ($).
- 6Read your cost per dose on the right — it updates as you type.
- 7Hit Share to keep the scenario or send it to someone.
About this calculator
Break a prescription price down to cost per dose and per day, then compare a brand price against a generic to see the annual difference and what a copay assistance program is worth.
Worked example
Using the values the calculator loads with:
Inputs
- Price per package: 240 $
- Doses per package: 30
- Doses per day: 2
- Generic package price: 22 $
- Your copay per fill: 35 $
Results
- Cost per dose: $8.00
- Cost per day: $16.00
- Annual cost (cash price): $5,840
- Annual cost on generic: $535
- Annual cost at your copay: $852
What each field means
Inputs
- Price per package ($)
- The price per package used in the calculation, measured in $. Starts at 240 $ so you have a working example on load.
- Doses per package
- The doses per package used in the calculation. Starts at 30 so you have a working example on load.
- Doses per day
- The doses per day used in the calculation. Starts at 2 so you have a working example on load.
- Generic package price ($)
- The generic package price used in the calculation, measured in $. Starts at 22 $ so you have a working example on load.
- Your copay per fill ($)
- The your copay per fill used in the calculation, measured in $. Starts at 35 $ so you have a working example on load.
Results
- Cost per dose
- Returned as a money amount in US dollars and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Cost per day
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Annual cost (cash price)
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Annual cost on generic
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Annual cost at your copay
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
Why is the cash price sometimes lower than my copay?
It happens more often than people expect, especially on cheap generics. Ask the pharmacy for the cash price before running it through insurance.
Do 90-day fills save money?
Usually yes — one copay covers three months instead of three copays, which this shows if you set doses per package accordingly.
Accuracy and limitations
- Population formulas describe averages; individual bodies vary, especially at the extremes of height, age, or muscle mass.
- Results do not account for medical conditions, medication, or pregnancy.
- Use this as a directional reference, not a diagnosis — talk to a clinician before acting on it.
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Medication Cost Per Dose Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/medication-cost-per-dose
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/medication-cost-per-dose" target="_blank" rel="noopener">Medication Cost Per Dose Calculator — RevenueLab</a> (2026).</p>
Source: [Medication Cost Per Dose Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/medication-cost-per-dose) (2026).